hmm, a bigger workspace, maybe the most obvious at the moment when working with it. But in my opinion, this plugin is so awesome that it deserves to be a standalone app. There are not much vector editors out there, this would be perfect for what it would be meant for, simple vector drawing with advanced features at the same time. Never thought about it ?
Another idea : integrate all of these features natively in paint.net, so it will turn into a hybrid editor with all of its basic features, plus simple vector drawing. All that combined with the power of plugins would make paint.net a tenor in the domain.